lib/strutil/replace.c

   1 /*
   2    Functions for replacing substrings in strings.
   3
   4    Copyright (C) 2013-2024
   5    Free Software Foundation, Inc.
   6
   7    Written by:
   8    Slava Zanko <slavazanko@gmail.com>, 2013;
   9
  10    This file is part of the Midnight Commander.
  11
  12    The Midnight Commander is free software: you can redistribute it
  13    and/or modify it under the terms of the GNU General Public License as
  14    published by the Free Software Foundation, either version 3 of the License,
  15    or (at your option) any later version.
  16
  17    The Midnight Commander is distributed in the hope that it will be useful,
  18    but WITHOUT ANY WARRANTY; without even the implied warranty of
  19    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20    GNU General Public License for more details.
  21
  22    You should have received a copy of the GNU General Public License
  23    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  24  */
  25
  26 #include <config.h>
  27
  28 #include "lib/global.h"
  29 #include "lib/strutil.h"
  30
  31 /*** global variables ****************************************************************************/
  32
  33 /*** file scope macro definitions ****************************************************************/
  34
  35 /*** file scope type declarations ****************************************************************/
  36
  37 /*** forward declarations (file scope functions) *************************************************/
  38
  39 /*** file scope variables ************************************************************************/
  40
  41 /* --------------------------------------------------------------------------------------------- */
  42 /*** file scope functions ************************************************************************/
  43 /* --------------------------------------------------------------------------------------------- */
  44
  45 /* --------------------------------------------------------------------------------------------- */
  46 /*** public functions ****************************************************************************/
  47 /* --------------------------------------------------------------------------------------------- */
  48 /**
  49  * Replace all substrings 'needle' in string 'haystack' by 'replacement'.
  50  * If the 'needle' in the 'haystack' is escaped by backslash,
  51  * then this occurrence isn't be replaced.
  52  *
  53  * @param haystack    string contains substrings for replacement. Cannot be NULL.
  54  * @param needle      string for search. Cannot be NULL.
  55  * @param replacement string for replace. Cannot be NULL.
  56  * @return newly allocated string with replaced substrings or NULL if @haystack is empty.
  57  */
  58
  59 char *
  60 str_replace_all (const char *haystack, const char *needle, const char *replacement)
  61 {
  62     size_t needle_len, replacement_len;
  63     GString *return_str = NULL;
  64     char *needle_in_str;
  65
  66     needle_len = strlen (needle);
  67     replacement_len = strlen (replacement);
  68
  69     while ((needle_in_str = strstr (haystack, needle)) != NULL)
  70     {
  71         if (return_str == NULL)
  72             return_str = g_string_sized_new (32);
  73
  74         if (str_is_char_escaped (haystack, needle_in_str))
  75         {
  76             char *backslash = needle_in_str - 1;
  77
  78             if (haystack != backslash)
  79                 g_string_append_len (return_str, haystack, backslash - haystack);
  80             g_string_append_len (return_str, needle_in_str, needle_in_str - backslash);
  81             haystack = needle_in_str + 1;
  82         }
  83         else
  84         {
  85             if (needle_in_str != haystack)
  86                 g_string_append_len (return_str, haystack, needle_in_str - haystack);
  87             g_string_append_len (return_str, replacement, replacement_len);
  88             haystack = needle_in_str + needle_len;
  89         }
  90     }
  91
  92     if (*haystack != '\0')
  93     {
  94         if (return_str == NULL)
  95             return strdup (haystack);
  96
  97         g_string_append (return_str, haystack);
  98     }
  99
 100     return (return_str != NULL ? g_string_free (return_str, FALSE) : NULL);
 101 }
 102
 103 /* --------------------------------------------------------------------------------------------- */